/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.extensions.sql.meta.provider.datacatalog;



import io.grpc.Status;

import io.grpc.StatusRuntimeException;

import com.bff.gaia.unified.sdk.extensions.sql.UnifiedSqlTable;

import com.bff.gaia.unified.sdk.extensions.sql.meta.Table;

import com.bff.gaia.unified.sdk.extensions.sql.meta.provider.TableProvider;

import com.bff.gaia.unified.sdk.extensions.sql.meta.provider.bigquery.BigQueryTableProvider;

import com.bff.gaia.unified.sdk.extensions.sql.meta.provider.pubsub.PubsubJsonTableProvider;

import com.bff.gaia.unified.sdk.extensions.sql.meta.provider.text.TextTableProvider;

import com.bff.gaia.unified.sdk.options.PipelineOptions;

import com.bff.gaia.unified.vendor.guava.com.google.common.collect.ImmutableMap;



import javax.annotation.Nullable;

import java.io.IOException;

import java.util.HashMap;

import java.util.Map;

import java.util.stream.Stream;



import static java.util.stream.Collectors.toMap;



/** Uses DataCatalog to get the source type and schema for a table. */

public class DataCatalogTableProvider implements TableProvider {



  private Map<String, TableProvider> delegateProviders;

  private Map<String, Table> tableCache;

  private DataCatalogClientAdapter dataCatalog;



  private DataCatalogTableProvider(

      Map<String, TableProvider> delegateProviders, DataCatalogClientAdapter dataCatalogClient) {



    this.tableCache = new HashMap<>();

    this.delegateProviders = ImmutableMap.copyOf(delegateProviders);

    this.dataCatalog = dataCatalogClient;

  }



  public static DataCatalogTableProvider create(PipelineOptions pipelineOptions)

      throws IOException {



    DataCatalogPipelineOptions options = pipelineOptions.as(DataCatalogPipelineOptions.class);



    return new DataCatalogTableProvider(

        getSupportedProviders(), getDataCatalogClient(options.getDataCatalogEndpoint()));

  }



  private static Map<String, TableProvider> getSupportedProviders() {

    return Stream.of(

            new PubsubJsonTableProvider(), new BigQueryTableProvider(), new TextTableProvider())

        .collect(toMap(TableProvider::getTableType, p -> p));

  }



  private static DataCatalogClientAdapter getDataCatalogClient(String endpoint) throws IOException {

    return DataCatalogClientAdapter.withDefaultCredentials(endpoint);

  }



  @Override

  public String getTableType() {

    return "google.cloud.datacatalog";

  }



  @Override

  public void createTable(Table table) {

    throw new UnsupportedOperationException(

        "Creating tables is not supported with DataCatalog table provider.");

  }



  @Override

  public void dropTable(String tableName) {

    throw new UnsupportedOperationException(

        "Dropping tables is not supported with DataCatalog table provider");

  }



  @Override

  public Map<String, Table> getTables() {

    throw new UnsupportedOperationException("Loading all tables from DataCatalog is not supported");

  }



  @Override

  public @Nullable

  Table getTable(String tableName) {

    return loadTable(tableName);

  }



  private @Nullable

  Table loadTable(String tableName) {

    if (!tableCache.containsKey(tableName)) {

      tableCache.put(tableName, loadTableFromDC(tableName));

    }



    return tableCache.get(tableName);

  }



  private Table loadTableFromDC(String tableName) {

    try {

      return dataCatalog.getTable(tableName);

    } catch (StatusRuntimeException e) {

      if (e.getStatus().equals(Status.INVALID_ARGUMENT)) {

        return null;

      }

      throw new RuntimeException(e);

    }

  }



  @Override

  public UnifiedSqlTable buildUnifiedSqlTable(Table table) {

    return delegateProviders.get(table.getType()).buildUnifiedSqlTable(table);

  }

}